1. Field of the Invention
This invention relates to a method for producing a semiconductor device by dicing a semiconductor wafer covered with a protective sheet along scribe lines, a semiconductor device produced by the method, and a wafer detachment apparatus usable for the method.
2. Description of the Related Art
As disclosed in many documents such as JP-A-10-242253, JP-A-7-99172, U.S. Pat. Nos. 5,824,177, and 5,362,681, when a semiconductor wafer having plural movable portions is divided into plural chips, a protective sheet is attached to the semiconductor wafer to protect the movable portions. In this state, the semiconductor wafer is diced into the chips together with the protective sheet at a dicing-cut step.
In the conventional method described above, however, because the protective sheet is diced together with the semiconductor wafer, scraps of the protective sheet such as adhesive organic particles are produced by cutting and attached to the chips as contaminants. The scraps may be attached to electrodes formed on each chip to adversely affect the electrodes in electrical and mechanical connection.
Further, in the conventional method, the protective sheet needs to be removed from the chips after the dicing-cut step is carried out. If the protective sheet is bonded to the semiconductor wafer firmly, the removal of the protective sheet is difficult and may cause damage to the chips due to the resulting stress. Therefore, the protective sheet is bonded to the semiconductor wafer with a relatively small amount of adhesion. Because of this, the protective sheet is easily separated from the semiconductor wafer during the dicing-cut step. As a result, the protective layer cannot protect the movable portions sufficiently.
The present invention has been made in view of the above problems. An object of the present invention is to prevent a semiconductor device from being contaminated by scraps of a protective sheet produced when a semiconductor wafer covered with the protective sheet is cut by dicing to form the semiconductor device. Another object of the present invention is to provide a semiconductor device and a method for producing the semiconductor device capable of preventing separation of the protective sheet.
According to one aspect of the present invention, in a method for producing a semiconductor device, after a protective sheet is fixed to a jig, a dicing-cut region of the protective sheet is removed. Then, a semiconductor wafer is bonded to the protective sheet, and the jig is detached from the protective sheet and the semiconductor, whereby the semiconductor wafer is exposed from the dicing-cut region of the protective sheet. Then, the semiconductor wafer is cut by dicing along the dicing-cut region to form the semiconductor device.
In the method described above, because the dicing-cut region of the protective sheet is removed and the protective sheet is not cut by dicing, any scraps of the protective sheet are not produced by dicing. As a result, the semiconductor device is not contaminated by the scraps. Because a dicing blade does not contact the protective sheet, the separation of the protective sheet is not caused by the dicing blade.
According to another aspect of the present invention, a semiconductor device has a semiconductor chip provided by cutting a semiconductor wafer by dicing, and a protective member disposed on the semiconductor chip. A peripheral edge portion of the protective sheet is provided at an inside of the peripheral edge portion of the semiconductor chip. Because the peripheral edge portion of the protective sheet is provided at the inside of the peripheral edge portion of the semiconductor chip, a dicing blade does not contact the protective member when cutting the semiconductor wafer. Therefore, generation of scraps and separation of the protective member can be prevented.
The inventors have further studied and examined the method for producing the semiconductor device, and found out that when adhesion between the protective sheet and the jig was strong, the semiconductor wafer was easily broken when the protective sheet and the semiconductor wafer were detached from the jig.
To solve the problem described above, according to the present invention, the protective sheet and the semiconductor wafer are detached from the jig by a pressure applied to the protective sheet from a side of the jig. Accordingly, the semiconductor wafer can be detached without being damaged together with the protective sheet. Workability and throughput for detaching the semiconductor wafer from the jig are also improved.
Further, to solve the problem describe above, according to another aspect of the present invention, a wafer detachment device is used for detaching the semiconductor wafer and the protective sheet from the jig. The wafer detachment device has the jig for fixedly holding the protective sheet, and pressurizing means for applying a pressure to the protective sheet. Accordingly, the protective sheet is detached from the jig by the pressure together with the semiconductor device readily.